Mechanical dehydrator and roller mill



April 9, 1940. E. F. ALLEN y IEUHAIICAL DEl'lY-DRATOR AID ROLLERIIILLFund April 16. 193e 4 Sheets-Sheet 1 NVENTOR Engr/e FIA/len ATTORNEY Ap9, 1940. E. F. ALLEN I MECHANICAL DEYDRATOR AND ROLLER IILL,

Fil-ed April 16.' 1936 4 Sheets-Sheet 2 La mn. n. mk am El.l WA m -E .AI', /rvf 0B E April 9, 1940 E. F. ALLEN l 2,196,651

u EcHANIcAL DEHYDRA'roR No lROLLER um.

Filed April 16. 193 4 Sheets-Shset 3 82 Iricg INVENTOR Ear/e F.' A/[eATTORNEY April 9, 1940- E.v F. ALLEN 2,196,651

MECHANICAL bEHYDR-A'OR AND ROLLER IIILL Filed April 16. 1936 4Sheets-Sheet' 4 fit1 -5- 5i-.

:NVENTOR E'AELE F ALLE/v,

ATTORNEY Patented Apr. 9,

UNITED STATES MECHANICAL DEHYDRATORAND ROLLER Earle F. Allen,Briai'cliii' Manor, N. Y., assignor,

by mesne assignments, to Stacom Process Corporation, Long Island City,N. Y., a corporation vof New York Application April 16,

9 Claims.

This invention is a continuation in part of my co-pending applicationSer. No. 17,050, led April 18, 1935,for Mechanical dehydrator andprocess and apparatus, and consists mainly in the further development ofcertain of the various modifications of the original concept. disclosedin said earlier application.

The present application is particularly concerned with an apparatus inwhich the pressure applied by the inner roller is opposed by a roller yroll, the ring or hollow cylinder forming the other press member beingfreely rotatable and being driven by frictional surface contact with theinner roll, while in the prior application the power is applied to thering and the roll is driven by friction. Another feature of the presentinvention is theprovision of such an apparatus in which the axes of thering and rollers are in the same horizontal plane.

Also in the present application various forms and others shown insection on the plane denoted by the line I-I in Fig. 2 of a machineembodying my invention adapted to be operated by a worm driving gear.

Fig. 2 is a horizontal section on the irregular line 2-2 of Fig. 1,parts being broken away, and

Fig. 3 is a vertical section on the irregular line 3-3 of Fig. 2.

Fig. 4 is aside elevation with parts broken away of a gear driven typeof apparatus employing a powerful spring for compression instead ofhydraulic cylinders and having both the inner roll and the outeranti-friction roll positively driven by said gearing, and

Fig. 5 is a plan view of the device of Fig.- 4 with parts brokenaway andothers shown in section. v

Fig. 6 is a plan view with parts broken away and others shown insectionof a construction similar to that shown in Figs. 4 and 5 exceptthat an hydraulic cylinder is employed instead of a spring and only theinner roll is gear-driven, and

1936, Serial No. '14,625

(Cl. 10U-47) Fig. '1 is a vertical cross section taken on line 1-1 ofFig. 6.

Fig. 8 is a detail cross section with parts broken away of a ring andinner roll like that of Fig. 1, showing in addition a special form ofapparatus for feeding material continuously to the roll pass,

and v f Fig. 9 is a section on line 9--9 of Fig. 8.

Figs. 10 and 11 are perspective details of different forms oftelescoping coupling which may be inserted in. worm shaft I9.

Fig. 12 is a diagram of the horn angle between a pressure surfaces inthe machine of Figs. 4 and 5 and Fig. 13 is a similar diagram ofsubstantially the same angle reproduced in the larger machine of Figs. 1to 3.

Throughout the drawings like reference characters indicate like parts.

Referring to Figs. 1, 2 and 3, a two-part casing and frame is indicatedat I, in which the moving parts of the mechanism are enclosed andsupported. 2 indicates a freely rotating ring or open ended cylinderwhich may be provided with facing plates 23, 23, of harder material, andpreferably. of slightly less width than the main body of the ring 2,which as here shown is supported in and between circular grooves 3, 3,formed in the side plates of the main frame. 4 indicates an inner rolllocated within and in contact with the inner facing plate surface of thering 2 so that together they constitute a roll press when rotated. i 24is an outer anti-friction roll bearing on the outer surface of ring 2and supporting the same against the radial thrust 'of roll 4. 35 Shaft 5of roll 4 is journaled in slightly movable journal blocks 'I and 8 and 9is a cap for the front journal block. I0 is a fixed journal bearing forthe shaft 5 of roll 24'in the form of a rigid cap cast in the rear frameplate, and II is a similar front journal bearing, but left open at theouter end to be closed by cap I2.

Bolts for fastening together various portions of the casing includingthese caps 9 and I2 are shown at I3, I3. j

The openings in the casing sides for the movable journal blocks 'I' and8 are large enough to allow slight clearance for their horizontal motionwithin narrow limits, as indicated at I4, I4 (Fig. 2), and said blocksare mounted on the horizontally'extending splines I5, shown in crosssection in Fig. 3 and in dotted lines in' the other figures. I

`Thel shafts 5, 5, are provided with graphite bushings 6 and I6 whichare of the standard type u bushings having a plurality of fine radialperforations in each of which graphite is packed. When these are putinto use a film of graphite forms immediately on the innersurfaces ofsaid bushing or sleeve and persists indefinitely. The journal pressuresrequired in the operating of apparatus according to my invention are sogreat that ordinary methods of journal lubrication with oil can not beused. Worm wheels I1, I1, are held fast .on the front ends oi' rollshafts 5, 5, by keys 29, 29, and cooperate with right and lett handworms I8, I8, carried by the power shaft I9, which may be driven byanelectric motor such as that indicated at 82 in Figs. 5 and 6. Ballbearings for the worm shaft are indicated 'at 20, 28, and 2| indicates aspline connecting the v worm in the movable journal block 3 to the shaftin such manner that it may have thenecessary slight movement lengthwiseof the latter.` 'Ihis movement may, however, be otherwise rendered4possible as by making shaft I 9' in two sections connected by some kindof a longitudinally yielding coupling, such as indicated in Figs. 10 and11.

Removable plates 22, 22, of semicircular form are shown as being set inthe side walls `of the casing and have portions of the guide grooves 3,3, for the ring 2 cut intheir inner faces. Any necessary feed anddischarge opening should be cut in at least one of said plates, one suchbeing indicated at 25 in Fig. -1. Hydraulic cylinders 26, 26, areanchored to the frame and contain pistons 21, 21, connected to pistonrods or plung; ers 61, 61, which have their outer ends resting againstthe movable journal blocks 1 and 8 respectively. Fluid under pressure issupplied to the cylinders through pipes 28, 28.

The grooves 3 in plates 22 should have enough clearance to permit ring 2to always have full width bearings'on both rolls 4 and 24 when thepressure is applied by forcing liquid into cylinders 26, 26. Even whenthese cylinders are of medium size, say 41/2 inches in diameter, ahydraulic pressure of 2000 pounds or more to the square inch can easilybe created therein which will exert a thrust of about 60,000 pounds ormore on the shaft of roll 4 and force it against ring 2. If then thecellulose-bearing materials are fed between the opposite surfaces of 2and 4 in a thin ribbon, perhaps only a few inches in width, the cellstructures thereof are thoroughly crushed, and nearly allliquidycontents expelled. There should be an opening (not shown) in therear casing plate 22 on a level with the lowest portion of the interiorsurface of ring 2, through which opening the expressed liquids canescape and be collected in any suitable receptacle. With the liquid muchof the coloring matter and the noncellulose solids are also expelled.

In operating this embodiment of the invention oil or water is admittedto cylinders 26, 26, under very great pressure sufficient to produce athrust of from 5000 to 9000 pounds or more per linear inch of contactbetween the inner surface of plate 23 of ring 2 and the surface of roll4 (i. e., if the width of the roller is 4 inches the total force appliedby the roller will be 20,000 to 36,000 pounds), said thrust beingabsorbed, of course, by the anti-friction roll 24. Then when worm shaftI9 is rotated in a counterclockwise direction, looking at Fig. 3,`theinner roll 4 and ring 2 will be given rotation in a clockwisedirection, looking at Fig. l, and the anti-friction rollV 24 will bepositively rotated in a counterclockwise direction. Any materialintroduced through a feed amanti known as oilless bearings consisting ofImetal openingl such as 23 will then fall on the inner surface of therotating ring 2 and be carried up to the zone of maximum pressurebetween it and the inner roll, said line of greatest pressure extending,of course, along the horizontal plane in which the axes of shafts 5, 5,lie.

Any convenient form of roll scraper and discharge trough can beinstalled for removing the crushed material from the roll and ringsurfaces, such as one of those indicated in Figs. 4-7.

Referring to Figs. 4 and 5, the main frame is there marked 3|, the ring32, the inner roll 34, and the outer anti-friction roll 36. Thesupporting shafts for said rolls are indicated respectively at 35, 31,and a supporting idler for ring 32, shown at 33. In this constructionthe roll pressure is supplied to the external roll 36 by means of theextremely stiff helical spring 38, the shaft 31 of this rolly having acertain amount of horizontal play in the slots 39, 39, in the side wallsof the main frame 3I. Pressure of spring 38 is adjusted by means of thescrew 44 meshing in fixed nut 45 and carrying one-half oi ther thrustballbearing 43 at its inner end, the other half of said bearing beingcarried by the movable plate 42 which serves as a thrust member againstthe outer end of spring 36. The inner end of said spring bears againstthe pressure fork 4I in which the roll 36 is supported by means of hubs48, 40. Clips 46, 46, carried by said fork and bearing on the outer endsof said hubs serve to center the roll 36 in the fork.

lIn this construction, both rolls 34 and 36 are positively drivenbygearing from motor 62, said gearing comprising armature shaft pinion 41,gear 48 fast on countershaft 49 journaledin fixed bearings 60, 60, andcarrying pinion 50 which meshes with gear 5I fast on shaft 52, which isjournaled in and extends through the main frame, carrying the gear 53 onits front end whichmeshes with the intermediate gear 54, therebytransmitting motion to the gear 55 on the shaft 35 of the inner roll 34.The shaft 52 also carries gear 56 at the rear side of the casing whichmeshes with gear 51 on the shaft 31 of -the anti-friction roll 36, thuspositively driving the latter in an opposite direction to that in whichvthe roll 34 revolves. 58 indicates a combined scraper and dischargetrough supported on brackets 59, 59, and bearing against'the outersurface of inner roll 34, and the inner surface of ring 32, while 6I,6I, indicate Scrapers bearing against the side edges of ring 32. Inoperation the ring 32 and inner roll 34 are given rotation in acounterclockwise direction looking at Fig. 4 by rotation of the motor 62in the proper direction, while outer roll 36 is positively rotated in aclockwise direction. The material to be treated is fecl in beneath thescraper 58 to the lower horn angle between the ring 32 and the roller34. This material may be fed in by hand or-by a suitable mechanicalmeans, such, for example, as illustrated in Figures 6, 7 and 8.

Referring to Figs. 6 and 7, a construction generally similar to thatshown in Figs. 4 and 5 is illustrated except that only the inner roll14, carried by shaft 15 journaled in frame 1I, is positively driven, thering 12 and thrust roll 16 being frictionally driven therefrom. Thegearing rotating roll 14 is similarl to that shown in Figs. 4 and 5 andthe like parts are given like reference numerals.

Also in this form hydraulic cylinder 18 having piston 19 and inlet 60for pressure fluid is substituted for the pressure spring 38 of Figs. 4and 5,

the piston rod carrying they pressure fork 8| in which roll18 isjournaled.

The ring 12 and pressure roll 14 are given rotation in the samedirection as ring 32 and roll 34 in Fig. 4 by the motor and gearing,which are the same in both.

82 yindicates an inclined feed trough by'which raw material may bedschargedfinto the lower part of the interior of ring 12 and be carriedup by rotation of the ring into and through the pressure zone between itand roll 1l. An inclined scraper and discharge trough which bearsagainst the inner surface of the ring 12 and the outer surface of roll14 at points spaced-away 180 from the line of contactbetween said ringand roll is indicated at 83. An idler roller journaled in frame 1l forsupporting ring 12 is shown at 13 in Fig. 7.

My invention is operable on both dry and damp materials. With theformer, the feed may be continuous as the sole purpose then is thecrushing of the particles to utmost fineness, a thin layer of thematerials being continuously fed upward to the limited compression zonewhere it will be subjected to enormous pressure between the movingsurfaces of ring and roll. With the latter an additional and mostimportant object is expressing as much as possible of the containedliquids and the subsequent maintenance of the separation between suchconstituents which has been effected in the pressure zone.

The last mentioned result is besteffected by an intermittent feed of thematerials to the rolls when the simpler embodiments of the inventionhere shown are alone employed, the liquid expressed from any one charge`being given time to run down to the lowest portion of the ring interiorand out a-t one side thereof before the succeeding charge is dumped intosuch interior. It may. however, be attained in part with the use of acontinuous feed if a mechanism be installed such as that shown' indiagram in Figs. 8 and 9,

where la revoluble member or tedder, generally indicated at 90. is shownas journaled between side plates 22, 22, under the lower end of a feedchute or hopper 95, the upper end of which should protrude through afeed opening 25' in the rear plate. The tedder as there shown iscomposed of the-spool 9i having radial projections 92 uniformlydistributed around its surface.- These may be in the form of paddles, asindicated. 93 is a supporting and driving shaft for such spooloperatively connected by chain and sprocket gearing 94. or othermechanism to the shaft `Ei of roll l or other rotating element so as torevolve in the same direction as does ring 2. Beneath the tedder is ahorizontal screen 96. An outlet for liquid is shown at 91 in the frontplate .22.

a I In operation hopper 95 should be kept at least will be conveyed tothe pressure zone.

' 96, thence to ow out through drain opening 91.v

partially lled with the garbage, waste vegetav tion or other finelydivided fibrous material being treated. thus maintaining a mass of it 98on screen 96. The rotating tedder 90 will continuously flirt or pushsmall portions of this material to the left and distribute them in aneven layer on the upwardly moving, inner wall of ring 2 by which it Thethin film of liquid flowing downwards from such zone .will percolatethrough an upper, short section of the lowest stratum only of suchupwardly traveling layer of material and collect under screen r' Thusthe major portion of the incoming material will be kept out of contactwith the' expressed liquid and none of it will be dumped in the liquidbath below the screen, as it would be if such screen and tedder were notemployed.

Fig. 10 is a perspective detail of a. modification comprising atelescoping couplingv 8l in worm `shaft I'9to take the place of thespline 2l shown 6 in Fig. 1 in the worm I8 driving the movable roll l4,and is an air opening therein to prevent air than to hide it in movablejqurnan mock 1, as. 20' indicated in Fig. 1.

As the high pressures employed in using my invention produce a largeamount of friction if there is any relative movement between theadjacentsurfaces of ring and roll, when in contact or when 25 having only a verythinlayer of material between them, and that would absorb a considerableamount of extra power in operating the press, I usually prefer to sodesign the gearing that each pair of surfaces thus in rolling contact'(or ap- 30 proximating such contact) shall have the same peripheralspeed.

When both inner and outer rolls are positively driven by the gearing, asin Figs. 1 to 5, it is necas essary that the surfaceA of the outer rollsshall travel'as much faster than does that of the inner one as the speedof the outer surface of the ring exceeds that of its inner surface-toaccomplish the above stated desired result. l In the constructions shownthis result is obtained by making the 40 length-ratio between the radiiof the inner and outer rolls the same as that between the ring interiorand exterior, and then having trains of driving gear for the two rollsdesigned to give each the same'number of revolutions per minute. Thesame result could, of course, be accomplished by having the revolutionsper minute of each vary inversely as the inner and outer radii of thering. while the radii of the rolls were made equal one 50 to another.

In all constructions in which one of thev pres' sure elements (ring androll) is frictionally driven by the other there is necessarily a certainamount produce a minute 'difference 'in their respective 'peripheralspeeds, especially when the layer of material being compressed betweenthem isx somewhat slippery in character, as would be the case with mostfibrous matter and garbage. It may 50 be that such action, whichundoubtedly occurs to a minute extent, is helpful because it produces aslight grinding effect on the ribbon of material when going through thezone of maximum pressure. Any such action would, of course, be ag- 05gravated by the modification shown in Figs.l 6 and '7 in which only thepressure roll is gear driven and both ring and anti-friction roll aredragged around by friction.

In all cases the high pressures used so compact 70 as well as crush, theparticles of material going through the roll pass-that they issuetherefrom as a thin, self sustaining ribbon made up of minute, coheringparticles, usually adhering to the surface' of the ring or of the roll.Particularly 75 pressure applied to successive minute areas of thinlayers thereof by my apparatus causes the contained liquid to burst all,or nearly all of the cells of such material cellulose, and thereby putthe crushed particles in the best possible condition for subsequentrapid and nearly complete air drying. This is a most important novelfeature of lmy process and apparatus whether used to prepare garbage foruse as a fuel, or to prepare any natural cellulose for further treatmentin paper making or other of the known commercial processes in which purecellulose is employed.

The greater portion of the crushed material usually leaves the pressurezone in the form of a compacted ribbon which adheres to the ring 2 untilit is scraped off and so broken into' fragments.

In designing apparatus embodying my invention a compromise betweenconicting conditions or limitations is required. On the one hand thehorn angle formed between the cross sections of the approaching surfacesof ring 2 and inner roll 4 must be sufhciently acute to prevent thematerial approaching its apex from slipping backward and so failingtoenter the zone of maximum pressure, which means that the diameter of theroll must be fairly large in proportion to that of the ring interior. Onthe other hand the roll diameter must not be so large as to so restrictthe space left between the other, opposite, surfaces of roll and ring asto unduly cramp and limit the space between said surfaces required forinstallation and operation of an efficient feeding mechanism.

In my original small machine, the proportions of which are accuratelyshown in Figs. 4 and 5, the diameter of ring'32 was 9 inches and thediameter of roll 34 was 6 inches. This produced a horn anglesatisfactory for the purpose but left no sufficient space for a feedmechanism, and consequently the material was fed by hand into thatmachine.

If the same proportion between diameters is f.

preserved in a larger machine the horn angle will be even more acute andAat least equally effective in action, but the free space then left forfeeding mechanism, while-larger, might not be sufficient l the same hornangle used in such first appara--V tusat least until further experimentsshow some permissible increase in its acuteness to be safe and perhapsadvantageous. Consequently I have shown in the machine of Figs. 1 to 3 arelative proportion of 2 to 1 between the diameters of ring and rollinstead of the 3 to 2 proportion of Fig..

4. With aring diameter of 20 inches this reproduces substantially thesame angle as the 9 and 6 inch dimensions of the original machine, andyet leaves suiicient free space for a feeding mechanism such as shown inFigs. 8 and 9, while keeping the over-al1 dimensions of the apparatuswithin convenient limits.

The shaded areas marked A in Figs.v 12 and 13 indicate about how far theoperative section of the horn angie would extend when a layer ofmaterial of the predetermined thickness is being fed to the pressurezone on the inner surface of the ring. That is to say, no layer ofmaterial thick enough to be compressed at all before it had travelled toabout the point P during rotation of either ring 2 or 32would ever bedeposited thereon if the feed mechanism lwere properly adjusted.

In Fig. 12, showing this horn angle as existing in my first machineillustrated in Figs. 4 and 5,

this point P as shown has been located arbitrarily on arc 32 in Fig. 12at a distance from the zero point on the scale there shown of about 21/2inches, i. e., P-O equals 2.5 inches. The outer limit of the compressionzone which begins there would be substantially indicated by the r'adiusR of arc 32 passing through P and the center C of the ring. Such radiusintersects arc 34 (struck from the center c of the roll) at X, and thedistance P-X represents substantially the width of the mouth of theassumed standard horn angle which has been tried out successfully in themachine of Figs. 4 and 5.

"I'he problem in designing another machine in which this standard hornangle of Fig. 12 is to be reproduced as nearly as possible, can besolved graphically as follows:

The radius R of the ring interior 2 of such second machine will beiixedby considerations of desired over-all dimensions, &c. If such radius isto be 10 inches, as in Figs. 1 and 13, the arc 2 of such a circle ofthat radius should be drawn through the zero point on the scale from acenter on the horizontal line 0-Z, such center not being shown in Fig.13 because of limitation oi' space.

On this are the point P should be located at' the 4 same distance O-P of2.5 inches from-0. A radius R of circle 2 is next drawn through Ptherein, as shown in Fig. 13, and on it a` point X is so located thatthe distance P-X' will equal that of P-X in Fig. 12. Obviously thispoint X so located will be one in the circumference of the desired innerroll 4, and the final step is then to locate the center of that roll.This can be done by drawing a perpendicular line from the middle point Yof cord 0--X' intersecting the horizontal diameter O Z of circle 2, andsuch point of intersection c' will be the center of the desired rollcircle 4. Consequently the distance O-c' will be the radius r' of suchroll, and as previously stated this radius will be approximately 5inches and therefore a roll of 10 inches diameter cooperating with aring of 20 inches internal diameter will reproduce substantially thesame horn angle as exists in the smaller machine with the 6 inch rolland 9 inch ring.

'I'he possibilities as to-novel and unforeseen results obtained with theenormous pressures per minute unit of surface area of relatively thinribbons of material which are obtainable in the use of my invention haveopened up a whole new field of investigation. i l

So far as I can find the most costly type of reciprocating platen pressnow on the market can develop a pressure4 of only 2000 lbs. per squareinch, and as these presses are composed of so many parts which have tobe adjusted before each operation thereof and so much carefulmanipulation has to be exercised in charging and discharging the press,about an hour's time is consumed in each complete cycle of its`use. Inthe only type of roll press ever before used commercially, i. e., theordinary type in which the materlal passes between two oppositelydisposed cylindrical rolls, such material will not be"'drawn between theopposing convex roll surfaces after the pressures applied by them equalor exceed a few hundred pounds per lineal inch of the roll faces. Ascontradistinguished froml such prior apparatus, a press made accordingto my invention is practically continuous in operation and no part ofthe material slips back after being grasped between ,the approachingpressure surfaces no matter how great the pressure per unit of area, orper lineal inch of roll face, may be. Furthermore the zone of pressureis narrow circumferentially of the roll and ring and only a relativelythin layer of material of uniform thickness will be fed to that zonewhen the feed is properly adjusted. Consequently the total pressure perlineal inch applied to the roll is exerted on less than a square inch ofsurface area of such layer of material. The pressure along eachtransverse line of the surface of the ingoing ribbon of materialincreases, as it moves upward, from zero to the maximum attained whenpassing through the plane in which the axes of the roll and the ringboth lie. Consequently, if a pressure of say 9000 lbs. per lineal inchof roll surface be applied of the layer of material as it passes throughsaid plane. There is, obviously, no limit to the roll pressure that canbe employed, except the strength of the materials used, and Icontemplate the use of special alloy steels which, when casehardened,withstand a pressure of 12,000 lbs. per lineal inch. The hydraulicpressure producing apparatus will, however, be adjustable so that themill -can vbe operated under any lower pressure found in practice to besufficient when working on any particular material. Whenever these highpressures are employed the roll 4 is thereby thrust toward the innersurface of ring 2 with such force that they, together with any thinstratum of highly compressed material between their surfaces, form aliquid-tight seal along the mathematical line which would representsurface contact if no foreign material were between. This liquid-tightseal lprevents any slimy, liquid material, like a sewage sludge passingsaid line at all. Consequently in such case the adjacent surfaces ofroll and ring would -pass upward from the line of contact between themclean and dry, all such slimy material having been rolled backward anddownward from the lower border of the zone of high pressure.

Having described my invention, I claim:

1. A mechanical dehydrating apparatus, comprising an imperforaterevolvable hollow cylinder having an annularly smooth inner surface, animperforate revolvab-le roller of somewhat less diameter than theinternal diameter of said cylthe .axis of the cylinder and the lowestpoint in its inner surface, a roller bearing upon the outer surface ofsaid cylinder substantially in the plane of said axes and throughout themajor portion of the width of contact of said pressing surfaces, meansfor forcing said rollers toward each other with great but yieldingpressure, and means for positively rotating one of said revolvablemembers in sucha direction that material vto be dehydrated may be fedinto the lower portion of the hollow-cylinder.

2. An apparatus as dened in claim 1 in which the diameter of the outerroller is suflciently larger than the diameter of the inner roller tohave the same peripheral speed as the outer surface of the ring whenrotated at the same angular speed as the inner roller, and means forpositively rotating said inner and outer rollers at the same angularspeed.

' 3. A mechanical dehydrating apparatus, comprising an imperforaterevolvable hollow cylinder having an annularly smooth inner surface anda Asubstantially horizontal axis, an imperforate revolvable roller, ofsomewhat less external diameter than the internal diameter of saidcylinder but at least equal to the radius of the cylinder, and having anannularly smooth outer surface and a substantially horizontal axis insubstantially the same horizontal plane as the axis of said cylinder,said roller being positioned within said cylinder and always in contactwith the inner surface thereof except when material is being pressedtherebetween, the line of contact of the roller and cylinder beingsubstan tially in the plane containing the axes of the roller'v andcylinder, a roller bearing upon the outer surface of said cylindersubstantially in the plane of said axes throughout the major portion ofthe width of contact of said pressing surfaces, means for forcing saidrollers toward each other with great butyielding pressure,and means forpositively rotating one of said revolvable members in suchv a directionthat material to be dehydrated may be fed into the lower portion of thehollow cylinder.v I

4. An apparatus as defined in claim 1 in which the outer roller is on ashaft carried in xed bearings and the inner roller is on a shaft movabletoward and fromthe shaft of said outer roller.

5. A mechanical dehydrating apparatus, cornprising an. imperforaterevolvable hollow cylinder having an annularly smooth inner surface anda substantially horizontal axis, an imperforate revolvable roller, ofsomewhat less external diameter than the internal `diameter of saidcylinder but at least equal to the radius of the ,cylinder and having anannularly smooth outer surface and a substantially horizontal axis insubstantially the same horizontal plane as the axis of said cylinder,said roller being positioned within said cylinder and always in contactwith the inner surface thereof except when material is being passedtherebetween, the line of contact of the roller andthe cylinder beingsubstantially in the plane containing the axes of the roller andcylinder, means for forcing said surfaces toward each other with greatbut yielding pressure comprising a second roller having its surface incontact with the outer periphery of the cylinder throughoutsubstantially the entire width of contact of said pressing surfaces, theaxis of one of said rollers being movable substantially horizontallytoward and from said cylinder, and means for positively rotating one ofsaid revolvable members Iin such a direction that material to bedehydrated may be fed into the lower portion of the hollow cylinder.

6. An apparatus as dened in claim 5 in which the axis of the other ofsaid rollers is in fixed bearings, and said axes are in substantiallythe same horizontal plane.

7. A mechanical dehydrating apparatus, comprlsing an imperforate, freelyrevolvable hollow cylinder having an annularly smooth inner sur- Ifaceand a substantially horizontal axis, an imperforate revolvable roller,of somewhat less external diameter than the internal diameter of saidcylinder but at least equal to the radius of the cylinder, and having anannularly smooth outer surface and a substantially horizontal axis insubstantially the same horizontal plane as the axis of said cylinder,said roller being positioned within said cylinder and always in contactwith the inner surface thereof except when material is being pressedtherebetween to provide pressing surfaces Within said cylinder, the lineof contact of the roller and cylinder being substantially in the planecontaining the axes of the roller and cylinder, a roller bearing uponthe outer surface of said cylinder substantially in the plane o! saidaxes and throughout the major portion of the width of contact of saidpressing surfaces, means actuated substantially in said plane forforcing said rollers toward each other with great but yieldingpressure,l and means for positively rotating said inner roller in such adirection that material to be dehydrated may be fed into the lowerportion of the hollow cylinder.

8. An apparatus as deilned in claim 7 in which the diameter of the outerroller is sufilciently larger than the diameter of the inner roller tohave the same peripheral speed as the outer surface of the ring whenrotated at the same angular speed as the inner roller, and means forpositively rotating said inner and outer rollers at the same angularspeed.

9. An apparatus as deilned in claim 1 in which the diameter of theroller is one-half to twolthirds the diameter of the cylinder.

EARLEF. ALLEN.

